In Orberg's Pensum A in Cap XXXIV he asks for the following to be scanned:

Now, I've mostly got this right but in the middle of two of the lines (as indicated) he has in the answer two verticallines. These indicate the end of a foot but also seem to divide the line so that what follows doesn't have any effect on the syllable length. I have marked these, 'II' on the 2nd and 4th line. Can anyone tell me how I can should be able to spot these because, otherwise, I'd have marked the 'is' in 'fallis' as short whereas with the dividing II it is marked long...

Similarly I wouldn't have divided up the feet as they are.... Is there something I'm missing?

pmda wrote:I don't understand your point about the consonantal 'i' in Iam.

Generally, when I starts a word and is followed by a vowel, it becomes a consonant sounding like our Y - iam is pronounced yam.

So, fallis jam (consonantal I is sometimes written as J) is scanned as fāllīs jām, since there are two consonants after the I in fallis.

The || represents the caesura (a pause), which is always at that place in a pentameter. In a hexameter, it usually goes on the third, fourth or second and fourth foot. It is placed where a word ends in the middle of a foot, usually after a long syllable. The links that Adrianus offered will explain better than I can.

Adrianus..what I mean is that I'm doing reasonably OK at scanning the meter and syllable length etc......but that the caesura 'II' somewhat threw me. I couldn't figure out any rules about where they went or why they went where they went (I found them in Orberg's Answer book which showed that I had got most of the scansion right.....but did not identify the caesuras...and hence did not appreciate that the first syllable of the following sentence was not influenced by the end of previous syllable but was treated like a new line...if you catch my drift.)